Medium and Heavy Trucks

Have truck repair questions? Ask an Expert

Connect one-on-one with {0} who will answer your question

I am working on a 1998 GMC C7500, with CAT 3126, No cruise…

Customer Question
I am working on a...
I am working on a 1998 GMC C7500, with CAT 3126, No cruise control. Truck will start when it wants to and will run for 30 min. and shutdown, like someone turned the key off. Check engine flashes. I cannot communicate with the ecm to pull codes. I have replaced timing sensors and harness because harness was in bad shape. I have the ecm off the truck right now at CAT hoping they can pull codes off of it. If not can you give me a schematic of the obd2 connector so I can figure out why I cannot communicate with this thing. I am using JPRO. VIN of Truck is*****************.
Thanks, Wade
Submitted: 1 year ago.Category: Medium and Heavy Trucks
Show More
Show Less
Ask Your Own Medium and Heavy Trucks Question
Answered in 35 minutes by:
3/4/2021
Technician: Wayne, Journeyman replied 1 year ago
Wayne
Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 17,777
Experience: worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling
Verified

Hi Wade,

I'm Wayne.

I'll be assisting you with this issue today.

Thank you for coming to Just Answer

Your Question is as important to us as it is to you.

I am sorry to hear you are having this issue.

I go offline between 3-4 Pm CST. M-F

Weekend 2-3 pm CST for the day.

Wayne

Wait to get the ECM back from CAT, that is the issue you are not getting codes,

also, ask Cat to update the software.

Wayne

Ask Your Own Medium and Heavy Trucks Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a technicianLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Wayne Your Own Question
Wayne
Wayne
Wayne, Journeyman
Category: Medium and Heavy Trucks
Satisfied Customers: 17,777
17,777 Satisfied Customers
Experience: worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling

Wayne is online now

Related Medium and Heavy Trucks Questions
Cat 3126e can't scan the ecm through the obd2 port. Tried
Cat 3126e can't scan the ecm through the obd2 port. Tried with j pro, cat ET & a snap on heavy duty scanner can't get any signal from it. It's on a early 2000s Chevy Kodiak. Ecm is working the truck r… read more
catmastertech
catmastertech
Field service technician
Vocational, Technical or Trade Scho
1,325 satisfied customers
I'm having communication problems with an 04 Freightliner
I'm having communication problems with an 04 Freightliner century with a C12 acert. no comms with the laptop and the dash says no data link. not sure where to go next.… read more
Nich1019
Nich1019
Diesel Technician
Vocational, Technical or Trade School
64 satisfied customers
Looking to take out a 7 speed manual out of a c7500 and
Hello, looking to take out a 7 speed manual out of a c7500 and replace it with an allison off of a 3116 cat, but I have a 3126 cat. just looking for positive confirmation that the back of the engines … read more
Mike Mcmillan
Mike Mcmillan
Triage Tech/Shop Foreman
Associates
591 satisfied customers
Crank no start. This is a 99 GMC C7500 with the cat 3126
this is a 99 GMC C7500 with the cat 3126 engine I have a JPRO Scanner and scanner not reading oil pressure … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
I am working on a 98 gmc c7500 with 3126 Cat that I could
I am working on a 98 gmc c7500 with 3126 Cat that I could not get started. I checked powers and grounds and I found o had no key switch power to pin 70. I jumped key switch power to that pin. Truck st… read more
Gary A.
Gary A.
Associates in Diesel Technology and Business Management
8 satisfied customers
Working on a 3126 cat in a 1998 chevy c7500. It cranks but
Working on a 3126 cat in a 1998 chevy c7500. It cranks but will not start. I have replaced speed sensors and harness. I have replaced ecm and verified grounds and power to ecm. I have replaced injecto… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
I am working on a 1998 Chevy C7500 with 3126 Cat. Need a
I am working on a 1998 Chevy C7500 with 3126 Cat. Need a wire schematic for OBD2 connector. Cannot communicate with engine ecm. I purchased the correct comm port cable for this application. I would li… read more
BrentR718
BrentR718
14 satisfied customers
1998 chevy c7500. No crank. Looking for ignition wiring
1998 chevy c7500. No crank. Looking for ignition wiring diagram. … read more
BrentR718
BrentR718
14 satisfied customers
I'm wanting to swap out my 8yl 3126 out of 2000 c7500 I want
I'm wanting to swap out my 8yl 3126 out of 2000 c7500 I want to put in ckm 2002 3126 for more power Don't know if I use old ecm or new on because for gauges ect … read more
Nich1019
Nich1019
Diesel Technician
Vocational, Technical or Trade School
64 satisfied customers
1999 C7500 CAT 3126. THE COMPUTER FRIED. I installed a reman
1999 C7500 CAT 3126. THE COMPUTER FRIED. I installed a reman one programmed to my engine serial #. The engine starts and runs for about 30 seconds and shuts off. I connected my cheap scanner and it is… read more
Mike Mcmillan
Mike Mcmillan
Triage Tech/Shop Foreman
Associates
591 satisfied customers
2004 gmc C7500, 2004 gmc C7500, 2004 Gmc C7500 vin
2004 Gmc C7500 vin 1GDL7C1CX4F514357 With a Caterpillar C7 esn# ***** Engine quit. Had no fuel pressure and no codes. I replaced Huei pump and injectors. Fished and clean per Caterpillar tsb. Oil,fuel lube and filters changed. Truck would not start after priming. Pulled codes again. Now I have a number 1 injector fault. Replaced injector harness due to bad connection at 1/2 injectors. Clear codes no start. Now codes on all 6 injectors. Replaced and reflash ECM. Now truck starts, idles and will not accelerate over 1500 rpm. Now has a 231-11 J1939 data link fault (58) now I'm trying to determine my next step. I'm in the middle of performing a power train data link circuit test. But I'm running out of options. In addition this truck is equipped with a gmc upfit to accommodate a Altec bucket. So there is a possibility there could be a issue with the cruise circuit ect. Although on the computer everything seams to checkout. … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
1997 Freightliner FL70 with 3126 Cat Engine and Automatic
1997 Freightliner FL70 with 3126 Cat Engine and Automatic Transmission.The Water\Oil light is coming on intermittently along with a buzzer. Can someone help me trouble shoot this? I don't want to arbi… read more
FIX-IT
FIX-IT
Comercial transport technician
Vocational, Technical or Trade Scho
829 satisfied customers
2003 gmc C7400 has a 3126E Cat. Gmc C7500 2003. Has a 3126E
Yes it came in last week with a shutdown problem. I replaced all the injectors because it had a code set for the #2 and #5 injector. … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
I have a 2003 GMC 7500 with a 3126 cat, truck came in no
Hello, I have a 2003 GMC 7500 with a 3126 cat, truck came in no start no crank, could not communicate with ecm, checked power and grounds found all ok, replace ecm, now I can communicate with ecm and … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
2011 kenworth t700 paccar mx pmc1-2, i have a code u1104
i have a code u1104 adaptive cruise control (acc1) … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
2001 GMC T8500 with CAT 3126, intermittent check engine
2001 GMC T8500 with CAT 3126, intermittent check engine light, engine loss of power after running for aprox 1 hours. Can not connect with Prolink Ultra, can not see any modules on the network. No wiri… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
6,062 satisfied customers
1999 GMC C7500 3126 Cat. Occasional hard start. "No ECM
1999 GMC C7500 3126 Cat. Occasional hard start. "No ECM detected" when hooking up scanner.… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
I have a 2000 gmc c7500 with a 3126 cat in it. We hooked a
I have a 2000 gmc c7500 with a 3126 cat in it. We hooked a Cat Et up to it this evening with the right adapter I assume...7x-1714. The Cat et program says 1 ECM detected...initializing but not does an… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
5,353 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Daniel Wilson

Daniel Wilson

6,062 satisfied customers

Owner at DJ Wilson

Cat Man

Cat Man

Cat Engine Expert

5,353 satisfied customers

I am ASE Master Truck Certified.

Wayne

Wayne

Journeyman

17,777 satisfied customers

worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling

Jeremy

Jeremy

Certified Truck/Bus Technician

2,756 satisfied customers

ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, Network Engineer specializing in CAN faults, Aftertertreatment, and vehicle communications

Curtis B.

Curtis B.

Technician

1,947 satisfied customers

Technician turned service manager on multiple lines of trucks and engines, used in industry.

cumminsdr

cumminsdr

Mechanic

1,886 satisfied customers

All types of Cummins applications

Chris (aka-Moose)

Chris (aka-Moose)

Technician

641 satisfied customers

24 years of experience diagnosing & repairing

< Previous | Next >

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x